The invention relates to an electric lamp based without cement. An electric lamp based without cement is disclosed in U.S. Pat. No. 4,412,273. The lamp described therein is a single base incandescent halogen lamp for use in a motor-vehicle headlight. The lamp in U.S. Pat. No. 4,412,273 consists of a lamp base made of metal and plastic parts. The lamp base has a cup-like metal fastening ring, a metal support sleeve and a plastic base which is provided with the electrical connections for the lamp. The support sleeve protrudes telescopically out of the base in which it is anchored, and is welded to the fastening ring using a plurality of integrally formed welding tabs. The fastening ring has a recess in which the end of the pinch of the lamp bulb is fixed. The plastic base has an annular flange and an alignment plate. Between the flange and the alignment plate, there is an annularly extending groove for receiving a gasket which seals off the reflector opening. The alignment plate ends approximately at the inner side of the reflector.
A disadvantage of the lamp in U.S. Pat. No. 4,412,273 is that the plastic alignment plate for the base is directly exposed to the infrared radiation emitted by the lamp. Because the plastic tends to give off vapors when heated, exposure of the plastic alignment plate to the infrared radiation results in fogging of the reflector. Furthermore, the plastic has a comparatively high coefficient of thermal expansion, so that heating the alignment plate by the infrared radiation generated by the lamp causes a misalignment of the light source. In addition, the telescopic design of the support sleeve has the disadvantage that the lamp has a comparatively large overall length and requires correspondingly deep reflectors.